<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta http-equiv="X-UA-Compatible" content="IE=edge" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Document</title>
    <style>
      body {
        background-color: black;
      }
      .time {
        width: 32%;
        height: 100%;
        color: #fff;
        font-size: 200px;
        text-align: center;
        line-height: 700px;
        /* background-color: #ccc; */
        float: left;
        margin-right: 20px;
      }
    </style>
  </head>
  <body>
    <h2 id="time"></h2>
    <button type="button" onclick="start()" id="start">开始</button>
    <button type="button" onclick="end()" id="end" disabled>停止</button>
    <hr />
    <div id="hours" class="time">00</div>
    <div id="minutes" class="time">00</div>
    <div id="seconds" class="time">00</div>
    <script src="index2.js"></script>
  </body>
</html>
